Embolization device and apparatus including an introducer cartridge and method for delivering the same

ABSTRACT

An embolization device comprising an elongate coil having a plurality of turns formed of a metal which is relatively opaque to x-rays and having rounded ends. A group of fibers is provided. The group of fibers has an intermediate portion and first and second end portions. The intermediate portion is looped about one of the turns to form a loop on one of said turns. The end portions extend interiorly of the coil and outwardly of the coil through two adjacent turns adjacent the turn about which the loop is formed. The ends of the fibers of the end portions of each group are free to move. The group of fibers is free of knots. The loop serves as the sole means for retaining the group of fibers on the coil.

This invention relates to an embolization device and an apparatusincluding an introducer cartridge and method for delivering the same inan intravascular procedure.

BACKGROUND OF THE INVENTION

Embolization devices have heretofore been provided which can be used inintravascular procedures. Typically such prior art devices have usedcoils with fibers attached to the coils. In certain embodiments, thefibers are merely retained by friction between the windings of the coilmaking it possible for the fibers to become separated from the coil. Inother embodiments, the fibers have been tied by knots to the windings ofthe coil, making the exterior surface of the coil lumpy or bumpy.

Apparatus heretofore provided for delivering such embolization coils tothe site have included cartridges for carrying the embolization coilsand typically have been in the form of stainless steel tubes serving asshipping containers and also serving as introducers for the coils whenthey are being introduced into a delivery catheter. It has been foundthat such stainless steel cartridges do not interface well with thecatheter hub making it difficult to introduce the embolization coil fromthe stainless steel tube and traverse the part of the hub of thecatheter before entering the passage of the catheter. There is thereforea need for a new and improved embolization device and a cartridge as apart of an apparatus and method for delivering the embolization deviceto the desired site in the intravascular system.

SUMMARY AND OBJECTS OF THE INVENTION

In general, it is an object of the invention to provide an embolizationdevice and an apparatus and method for delivering the same to anintravascular site.

Another object of the invention is to provide an embolization devicewith the fibers carried thereby being securely attached thereto withoutproviding bumpiness to the exterior surface of the embolization device.

Another object of the invention is to provide an introducer cartridgefor use in the apparatus and method which has a distal extremity whichis tapered to permit it to proximally engage the catheter hub tomaintain the alignment of the cartridge with the catheter hub.

Another object of the invention is to provide a cartridge of the abovecharacter in which the distal extremity is tapered to facilitate deeperpenetration of the introducer cartridge into the catheter hub.

Another object of the invention is to provide a cartridge of the abovecharacter in which the friction fit between the introducer cartridge andthe catheter hub maintains the alignment of the distal extremity of thecartridge with the internal diameter or passage of the catheter attachedto the catheter hub.

Another object of the invention is to provide an introducer cartridge ofthe above character which is transparent so that movement of theembolization device in the same can be visualized.

Another object of the invention is to provide an introducer cartridge ofthe above character in which a stylet can be utilized to advance theembolization device out of the introducer cartridge.

Additional objects and features of the invention will appear from thefollowing description in which the preferred embodiments are set forthin detail in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an embolization device which has a "C" orcircular shape incorporating the present invention.

FIG. 2 is a plan view of another embodiment of an embolization deviceincorporating the present invention which is in straight.

FIG. 3 being an enlarged partial side elevational view of a portion ofan embolization device incorporating the present invention showing themanner in which groups of fibers are secured to the coil.

FIG. 4 is a view looking along the line 4--4 of FIG. 3.

FIG. 5 is a cross-sectional view of an introducer cartridge with coiland stylet for introducing the embolization device intravascularly.

FIG. 6 is a cross-sectional view looking along the line 6--6 of FIG. 5.

FIG. 7 is a side elevational view showing a catheter assembly consistingof an introducer catheter and a guiding catheter used as the apparatusfor delivering the embolization device to the intravascular site.

FIG. 8 is a cross sectional view taken along the line 8--8 of FIG. 7.

FIG. 9 is a side elevational view of the delivery catheter used in theapparatus.

FIG. 10 is a partial cross sectional view showing the manner in whichthe distal extremity of the introducer cartridge is introduced into thehub of the delivery catheter.

In general, the embolization device is comprised of an elongate coilhaving a plurality of turns and formed of a metal which is relativelyopaque to x-rays. At least one group of a plurality of fibers is securedto the coil. The group of fibers has an intermediate portion and firstand second end portions. The intermediate portion is looped about one ofthe turns to form a loop which encircles said one turn and so that thefirst and second end portions extend interiorly of the coil and thenoutwardly from the interior of the coil through two adjacent turns onopposite sides of the loop so that the first and second ends are free topermit the fibers in the first and second ends to move about.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

More particularly as shown in FIGS. 1 and 2 in the drawings, theembolization device 11 is comprised of a coil 12. The coil 12 consistsof a plurality of helically wound turns 13. The coil 12 is formed of ametal which is relatively opaque to x-rays and may be made of a materialsuch as stainless steel, copper, gold, or platinum alloys. Because oftheir higher radiopacity, a platinum alloy is preferred, as for examplea platinum alloy 479 supplied by Sigmond Cohn. The coil 12 can have aprimary outside diameter ranging from 0.2 millimeters to 1.3 millimetersand can have a length ranging from 2 millimeters up to 90 millimeters.The wire utilized for forming the coil can have a suitable diameterranging from 0.002" to 0.006". For a coil having an outside diameter of0.4 millimeters, the wire utilized can have a diameter of 0.003".

Typically, the bulk material from which the coil is made is shipped in aprimary winding of the desired wire size and outside diameter. The bulkmaterial may then be wound into a secondary coil with secondary outsidediameters ranging from 2 millimeters to 10 millimeters. The coil 12 isthen cut into appropriate lengths for making coils in accordance withthe present invention. Typically, the coils are cut to a length of 1millimeter longer than the desired length to allow for loss duringmelting of the ends as hereinafter described. The coil 12 is providedwith an intermediate portion 12a and first and second end portions 12band 12c. The coil 12 can be placed in a fixture (not shown) and then thefirst end portion 12b can be advanced into a torch flame until the endof the coil melts into a smooth, rounded end 16. The fixture can then bereversed and the other end portion 12c advanced into the flame to form arounded end portion 17 as shown in FIG. 2 of the drawings. After therounded ends 16 and 17 have been formed, the coil 12 can beultrasonically cleaned.

Thereafter, the coil can be placed in another fixture, as for example atube which is then placed in a pin vise for holding the same for fiberattachment. For this purpose, a suitable length of yarn, as for example10" is cut from a coil of the yarn. The yarn is formed of a suitablesynthetic medical grade material such as Dacron. The yarn is comprisedof a plurality or groups 21 of filaments or fibers 22 of a suitable sizesuch as 30 Denier. The group 21 of fibers 22, in other words, thecut-off piece of yarn is then taken and gently pushed between turns 13in a predetermined location in accordance with the design for theembolization device. For example, only one group of fibers can beutilized or a plurality of groups of fibers can be utilized which arespaced a suitable distance apart, as for example 2 millimeters so thatthe number of groups of fibers is dependent upon the length of the coil.Each group 21 is pressed into the coil 12 between two adjacent turns 13.Then, by holding one end of the yarn or group, the other end is broughtback through the coil and then successively advanced through twoadditional turns of the coil. The yarn or group 21 is then brought backand looped over the last turn which has just been passed and thenprogressively advanced through two additional turns and then broughtback to the position shown in FIG. 3. Thus, it can be seen that the yarnor group of fibers 21 is provided with an intermediate portion 21a andfirst and second ends 21b and 21c. The group 21 of fibers, after it hasbeen looped about one of the turns of the coil 12 to form a loop 23 thatencircles the turn 13 extends from the intermediate portion 21a inopposite directions interiorly of the coil for at least one additionalturn and then outwardly from the interior of the coil between adjacentturns. In this way, the ends 21b and 21c of the group 21 are free toform something like tufts 26 extending along one side of the coil 12.The loop 23 serves as the sole means for retaining the group 21 offibers 22 on the coil 12.

As can be seen in FIG. 1, when the coil 12 is of a suitable length,additional groups of fibers 21 and can be spaced apart longitudinally ofthe coil and can be secured in the same manner as hereinbefore describedand as shown in FIGS. 3 and 4. Thus, the tufts 26 spaced apart asuitable distance, as for example approximately 2 millimeters along thelength of the coil 12. By way of example, the embolization device 11 canhave a coil external diameter of, for example, 2 millimeters and anextended length of 6 millimeters.

In addition to the straight shape for the coil 12 shown in FIG. 2, acurved coil 32 can be, provided which is circular or C-shaped as shownin FIG. 1. This C-shaped coil is formed by taking the primary winding 12and preforming a secondary winding to form the C-shaped coil 32 on acoil-winding apparatus. A tension line is place inside the primarywinding 12 and together are wound by a computer-controlled machine ontoa mandrel of specified diameter. The secondary winding is then removedfrom the mandrel and the shape is set in a furnace at a specified timeand temperature. The tension line is then removed from the secondarywinding. Tufts 33 are provided on the coil 32 and are formed in the samemanner as the tufts 26 shown in FIG. 2. As shown, they are provided onthe exterior circumferential surface of the coil and are spaced apart asuitable distance, as for example the 2 millimeters utilized inconjunction with the tufts in FIG. 2. The coil 32 is provided withrounded ends 36 and 37 formed in the same way as the ends 16 and 17 forthe coil 12 in FIG. 2.

The C-shaped embolization device 32 as shown in FIG. 1 is shown in itsat rest or normal position. The embolization device can be in theC-shaped form which is shown in FIG. 1 or, alternatively, it can be in astraight form such as shown in FIG. 2. However, it is provided loadedinto a cartridge 41. The C-shaped coil 32 can be straightened to theconformation as shown in FIG. 2 and then it can be loaded into theintroducer cartridge 41. The introducer cartridge 41 as shown in FIGS. 5and 6 consists of an elongate tubular member 42 formed of a cleartransparent plastic such as a radiation sterilizable polycarbonate. Itis provided with the passage 43 extending therethrough. It can have asuitable size, for example, an inside diameter of 0.023" and an outsidediameter of 0.060". Even though the tubular member is bendable, it isstill relatively rigid so that it can be utilized as an introducer ashereinafter described. The elongate tubular member 42 is provided withproximal and distal extremities 46 and 47. The distal extremity isprovided with a tapered tip 48. The introducer cartridge 41 can have asuitable length ranging from 3" to 5", as for example 4.875". The tip 48can have a suitable length such as 0.3". The tip 48 is tapered with theoutside diameter decreasing from the 0.060" for the remaining portion ofthe tubular member 42 down to approximately 0.030" with the distalextremity of the tip of 48 being rounded at 49.

A hub 51 is mounted on the proximal extremity 46 of the elongate tubularmember 42 and is also formed of the clear radiation sterilizablepolycarbonate. The hub 51 is provided with a cylindrical recess 52 whichis sized to receive the proximal extremity 46 of the elongate tubularmember 42. The cylindrical recess 52 opens into a tapered conical recess53 which has a proximal extremity sized so that its interior diameter at54 of approximately 0.020" is slightly less than or equal to theinterior diameter of 0.023" of the passage 43 in the elongate tubularmember 42. The proximal extremity 46 of the elongate tubular member 42abuts a shoulder 56 provided in the hub 51. The shoulder 56 extends overor aligns with the proximal extremity of the elongate tubular member 42.The conical recess 53 can have a suitable length, for example 0.44". Theconical recess 53 subtends a suitable angle, as for exampleapproximately 9° from the horizontal and adjoins another conical recess57 which subtends an angle of approximately 3°. The conical recess 57can have a suitable length as, for example 0.356". The hub 51 is alsoprovided with a circular flange 58 approximately midway of the conicalrecess 53 and extending radially or outwardly therefrom. The flange 58may be provided with a flat (not shown).

As can be seen in FIG. 5, the embolization device 11 is disposed withinthe passage 43 of the introducer cartridge 41. Because of the smallsize, the embolization device 11 is typically introduced into theintroducer cartridge 41 under a microscope. A tweezer (not shown) isutilized to pick up the embolization device 11 and inserting it into theconical recess 57 and then advancing it into the conical recess 53 andover the shoulder 56 into the passage 43. Thereafter, it can beintroduced further into the passage 43 by the use of a stylet 61 (seeFIG. 5). The stylet 61 can be of a suitable length such as 8.375" andcan be formed of elongate wire 62 of a suitable diameter such as 0.018".It is provided with a rounded tip 63 on its distal extremity 64. Theproximal extremity 66 is formed into a circle of the suitable diameter,as for example 1/4", which serves as a handle 67 for using the same. Bygrasping the handle 67, the assembler can introduce the embolizationdevice 11 further into the passage 43 where it will be protected andremain therein until the embolization device is ready to be used ashereinafter described.

The stylet 61 can then be removed and packaged with the introducercartridge 41 for later use in a sterile package (package not shown).

Let it be assumed that it is desired to use the embolization device 32and the introducer cartridge 41 in connection with a medical procedureand apparatus to inhibit or stop hemorrhaging occurring in a vessel ofthe patient, that is, blood is flowing in an undesired manner and it isdesired to form a clot of the blood in the vessel. By way of example,the procedure can be utilized in connection with a brain hemorrhage.However, it should be appreciated that the procedure can be utilized inother small vessels in the body to form a clot or embolism in a desiredlocation.

Let it be assumed that a cut has been made in the femoral artery of thepatient and a femoral sheath (not shown) of the conventional type hasbeen placed in the femoral artery of the patient. The physicianperforming the procedure then takes apparatus which includes aconventional guide wire, as for example a 0.038" diameter guide wire 71.The guide wire 71 is provided with a distal extremity which is veryflexible. This distal extremity is introduced into the sheath and thenadvanced through the femoral artery under fluoroscopy through the aorticarch and then through the carotid artery in the neck and then advancinginto the desired vessel in the brain to a location or site in which itis desired to place a catheter for forming an embolism in accordancewith the present invention.

As soon as the guide wire 71 is in place, a catheter assembly 76 (seeFIG. 7) forming a part of the apparatus is utilized which consists of anintroducer catheter 77 with a guiding catheter 78 disposed in the same.This catheter assembly 76 is advanced over the guide wire 71 ashereinafter described.

The introducer catheter 77 is comprised of a flexible elongate tubularmember 81 with a flow passage 82 therein. The introducer catheter 77 canbe of a suitable size, as for example 7.3 French and having a length of90 centimeters and a flow passage 82 with an inside diameter of 0.070".A female Luer fitting 83 is mounted on the proximal extremity 84 of theflexible elongate tubular member 81. The flexible elongate tubularmember 81 is provided with the distal extremity 85. The female Luerfitting 83 is releasably attached to a clamp assembly 86. The clampassembly 86 consists of a mating Luer fitting 87 of a conventional typeand has a relatively short flexible tubular member 88 mounted thereinwith a suitable outside diameter such as 3/16" and having a flow passage89 therein of a suitable diameter such as 1/8". The passage 89 isadapted to be clamped to a closed position by a releasable clamp 91 of aconventional type disposed on the tubular member 88. A female Luerfitting 92 is provided on the other end of the tubular member 88 andcompletes the clamp assembly 86. The clamp 91 is moved to the closedposition on the tubular member 88 at such time as all elongate elementshave been removed from passage 89, to prevent the flow of blood from theintroducer catheter.

The guiding catheter 78 consists a flexible elongate tubular member 94.The guiding catheter 78 can be of a suitable size, as for example 5.0French and has a length of 110 centimeters and a flow passage 96 with adiameter of 0.044". A male Luer fitting 97 with stopcock is mounted onthe proximal extremity 98 of the flexible elongate tubular member 94which is also provided with a distal extremity 99. As can be seen fromthe drawings, the flexible tubular member 94 has a length which is greatenough so that the distal extremity 99 can extend out of the distalextremity of the introducer catheter 77. The fitting 97 has rotatablymounted thereon a threaded hub 101 which is adapted to mate with thefemale Luer fitting 92 carried by the clamp assembly extension tubularmember 88 so that the guiding catheter 78 can be remained engaged withthe clamp assembly 86. A stopcock 102 is formed integral with thefitting 97 and is provided with a handle 103 for moving it between openand closed positions with respect to the passage 96 in the flexibleelongate tubular member 94. The stopcock 102 is provided with a femaleLuer fitting 104 which is adapted to mate with a male Luer fitting 105carried by a conventional sidearm adapter 106. The sidearm adapter 106is provided with central arm 107 and a sidearm 108. A hemostatic valve109 of a conventional type is mounted on the central arm 107 and isadapted to have the guide wire 71 extend therethrough and is adapted tomake a seal therewith so that blood cannot flow out of the vesselthrough the valve 109. A stopcock assembly 111 is mounted on the sidearm108. It is provided with a male Luer-type fitting 112 which engages thefemale Luer fitting 113 provided on the side arm 108. It is providedwith a handle 114 for moving the valve between opened and closedpositions and a female Luer fitting 115.

With the guiding catheter 78 of the type hereinbefore described disposedwithin the introducer catheter 77 also hereinbefore described and havingthe distal extremity of the guiding catheter 78 extending beyond thedistal extremity 86 of the introducer catheter 77, the distal extremity99 is positioned over the guide wire 71 and then advanced through thesheath over the guide wire. The entire catheter assembly 76 is advancedat the same time with the guiding catheter 78 within the introducercatheter 77 until the distal extremity of the guiding catheter 78reaches the desired site determined by the previously positioned guidewire 71.

As soon as the distal extremity 99 is in the proper position, the 0.038"guide wire 71 is withdrawn and a smaller guide wire, typically 0.016" or0.014" guide wire 116 having a distal extremity 117 is inserted into acentral arm 107 of the sidearm adapter 106 and through the lumen orpassage 96 of the flexible elongate tubular member 94 of the guidingcatheter 78. The guide wire 116 is advanced so that it extends slightlybeyond the distal extremity 99 of the guiding catheter 78. At thisjuncture, the guiding catheter 78 is removed over the guide wire 116leaving the introducer catheter 77 with clamp assembly 86 in place.

A coil delivery catheter 121 is then utilized and is advanced over thesmall guide wire 116 until it reaches the desired location or site. Thecoil delivery catheter 121 as shown in FIG. 9 consists of a flexibleelongate tapered tubular member 122 having a proximal extremity 123 anda distal extremity 124. It is provided with a flow passage 126 having asuitable inside diameter, as for example 0.021" and the tubular memberhaving an outside diameter of 0.028" at distal extremity 124 and anoutside diameter of 0.039" at proximal extremity 123.

A female Luer-type hub 131 is mounted on the proximal extremity 123 ofthe flexible elongate tubular member 122. The female Luer-type hub 131is provided with a conical recess 133 which has a distal extremity 134with a diameter approximately the diameter of the passage 126, as forexample a diameter of 0.020"-0.023". The conical recess 133 is inclinedfrom the horizontal as viewed in FIG. 10 by a suitable angle, as forexample 6.52°, and has a suitable length, as for example approximately0.585". The conical recess 133 adjoins a conical recess 134 whichsubtends an angle from the horizontal of approximately 2°. The conicalrecess 134 has a suitable length, as for example 0.200".

As soon as this delivery catheter 121 has been advanced to the desiredlocation or site over the small guide wire 116, the small guide wire 116is removed.

The sidearm 106 can be utilized for the heparin-saline drip to keep theblood flushed out of the introducer catheter 77.

A sidearm adapter 136 is provided which has a central arm 137 and asidearm 138. It is provided with a male Luer fitting 139 which isthreaded onto the female hub 131. A hemostatic valve 141 is provided onthe central arm 137 and a stopcock 142 is provided on the sidearm 138and has a handle 143 for moving the stopcock between opened and closedpositions. The stopcock 142 is also provided with a male fitting adaptedto mate with the female fitting provided on the sidearm 138. It alsoprovided with a female-type Luer fitting 146.

When the delivery catheter 121 is advanced over the wire 116 to thedesired location, the valve 109 can be tightened to prevent bloodflowing from between the delivery catheter 121 and the sidearm adapter107. The valve 141 can also be tightened to prevent the flow of bloodbetween the guide wire 116 and sidearm adapter 136.

Once the delivery catheter 121 has its distal extremity 124 at thedesired location, the valve 141 can be loosened slightly and the guidewire 116 can be removed. Thereafter, the sidearm assembly 136 can beremoved. The sidearm may be removed or left attached. The cartridge willpass through the valve when sufficiently opened.

The introducer cartridge 41 is then taken with the embolization devicewithin the same and is pushed into the hub 131 to frictionally lodge itin the same by having its tapered extremity 48 engaging the taperedsidewall 134 of the female hub 131. By pressing introducer cartridge 41within the hub, the introducer cartridge is frictionally retained withinthe hub to hold it in place.

The stylet 61 is then taken and is advanced into the hub 51 and into thepassage 43 and engages the embolization device 11 therein and is used topush it out of the introducer cartridge 41 into the passage 126 in theflexible elongate member 122 of the delivery catheter 121. Theadvancement of the embolization device 11 can be readily observedbecause of the transparency of the introducer cartridge 41 and the hub131. As soon as the stylet 61 has advanced the embolization device 11into the passage 126 as far as it can be advanced by the stylet 61, thestylet 61 is removed. The small guide wire 116 is then taken and itsproximal end, which is the stiffer end, is introduced into the hub 131and into the passage 126 to engage the embolization device 11 and topush the embolization device 11 through the delivery catheter 121 untilthe embolization device 11 is near the distal extremity 124. Typically,the embolization device will be from 50 to 75 centimeters from theproximal end of the delivery catheter 121 at this point. Thereafter, thesmall guide wire 116 is withdrawn and is reversed with its more flexibledistal extremity 124 advanced into the hub 131 and into the passage 126until it again engages the embolization device 11. The guide wire 116 isthen pushed while being viewed under fluoroscopy until the embolizationdevice 11 exits from the tip of the delivery catheter 121. As soon asthe embolization device 11 has exited from the passage 126, it will thenassume its normal C-shape and engage the walls of the vessel in which itis disposed. Its tufts 33 (see FIG. 2) carried thereby will come intocontact with the blood in the vessel.

It should be appreciated that, if desired, additional embolizationdevices 11 can be placed in the same vessel at the same location in asimilar manner by utilizing a introducer cartridge and mounting the samein the hub 131 after the other introducing cartridge has been removed.

After the desired number of embolization devices 11 have been positionedat the desired location, the sidearm 136 can be removed and a contrastagent, as for example a radiopaque dye can be introduced directly intothe delivery catheter 121 to visualize directly the blood flow and thedegree of embolization which is occurring. When the degree ofembolization is satisfactory, the delivery catheter 121 can be removedfollowed by removal of the introducer catheter 77. The femoral sheathcan then be removed and the opening to the femoral artery can be suturedand, if desired, alternatively it can be temporarily closed by aconventional femoral artery closure (not shown). This makes it possibleto perform another embolization procedure if that proves to be necessaryto achieve the desired embolism in the vessel of interest.

It is apparent from the foregoing that there has been provided anintroducer cartridge and an apparatus which includes an embolizationdevice cartridge and a method for delivering the embolization device tothe desired location in a vessel of a patient. The embolization devicein the form of a coil has the fibers or filaments attached to the sameso that they cannot be accidentally removed from the coil. The coil hasa relatively smooth outer surface which does not have lumps or bumpswhich would be created by tying knots into the fibers to fasten the sameto the coil. In addition, there has been provided an introducercartridge which frictionally engages the hub of the delivery catheter sothat it cannot accidentally fall out. The introducer cartridge has beenformed of a transparent material as has the hub of the delivery catheterso that the movement of the embolization device within and from thecartridge can be readily observed.

What is claimed is:
 1. An embolization device comprising an elongatecoil having a plurality of turns formed of a metal which is opaque tox-rays and having rounded ends comprising a first group of fibers, saidfirst group of fibers having an intermediate portion and first andsecond end portions, said intermediate portion being looped about one ofsaid turns to form a loop on one of said turns, the first and second endportions extending interiorly of the coil and outwardly of the coilthrough two adjacent turns adjacent the turn about which the loop isformed, the ends of the fibers of the first and second end portions ofeach first group being free to move, said first group of fibers beingfree of knots and said loop serving as the sole means for retaining thegroup of fibers on the coil.
 2. A device as in claim 1, wherein togetherwith at least one additional group of fibers which are secured to thecoil in the manner in which the first group of fibers is secured to thecoil and being spaced longitudinally of the coil from the first namedgroup of fibers.
 3. A device as in claim 2, wherein said fibers extendoutwardly of the coil in the same direction.
 4. A device as in claim 1,wherein said coil has a normal C-shaped configuration having acircumference and in which the fibers extend outwardly from thecircumference of the coil.
 5. A device as in claim 1, wherein saidrounded ends are in the form of hemispherical ends.
 6. A device as inclaim 1, wherein said coil is formed of wire having a diameter ofapproximately 0.003" wherein said coil has an outside diameter of 0.4millimeters.
 7. A method for introducing an embolization device into avessel of a patient comprising introducing a first guide wire havingproximal and distal extremities into the vessel of the patient so thatthe distal extremity is disposed in the vicinity of the location inwhich it is desired to perform an embolization, introducing a catheterassembly comprised of a clamp assembly, an introducer catheter and aguiding catheter having proximal and distal extremities disposed in theintroducer catheter over the first guide wire until the distal extremityof the guiding catheter is disposed in the desired location removing thefirst guide wire, introducing a second guide wire having a proximal endand a distal extremity of a smaller size than the first guide wire intothe guiding catheter so that its distal extremity extends beyond thedistal extremity of the guiding catheter, removing the guiding catheterfrom the introducer catheter, advancing a delivery catheter havingproximal and distal extremities over the second guide wire until thedistal extremity of the delivery catheter is disposed in the vicinity ofthe desired location, said delivery catheter having a hub formed oil theproximal end thereof which has a conical recess therein, removing thesecond guide wire, placing an introducer cartridge having a flexibletubular member with proximal and distal extremities with the distalextremity being tapered so that the distal extremity frictionallyengages the conical recess in the hub of the delivery catheter, saidintroducer cartridge having a flow passage extending from the proximalextremity to the distal extremity of the flexible tubular member andhaving an embolization device disposed in the flow passage, said flowpassage having a diameter, the proximal extremity of the flexibletubular member of the introducer cartridge having a hub and having aconical recess therein and having proximal and distal extremities withthe distal extremity of the conical recess having a diameter of slightlyless than the diameter of the flow passage in the flexible elongatetubular member, introducing a stylet into the hub of the introducercartridge and advancing the stylet through the flow passage to push theembolization device out of the introducer cartridge and into a passageof the delivery catheter, removing the styler, taking the proximal endof the second guide wire and introducing it through the introducercartridge and into the passage in the delivery catheter to advance theembolization device to near the distal extremity of the deliverycatheter, withdrawing the second guide wire, inserting the distalextremity of the second guide wire into the passage in the deliverycatheter and advancing the second guide wire to force the embolizationdevice out of the distal extremity of the delivery catheter to move itinto the patient's vessel at the desired location and thereafterremoving the second guide wire, the delivery catheter and the introducercartridge.
 8. A method as in claim 7, together with the step of removingthe second guide wire, removing the introducer cartridge, inserting asecond introducer cartridge having an embolization device into the hubof the delivery catheter so that it is frictionally retained therein,using the stylet to advance the embolization device from the introducercartridge, utilizing the proximal and distal extremities of the secondguide wire to advance the embolization device out of the flow passage inthe delivery catheter to place a second embolization device in thedesired location, repeating the same sequence and steps until a desirednumber of embolization devices have been positioned in the desiredlocation in the vessel of the patient.
 9. An introducer cartridge and anembolization device for use with a delivery catheter having a proximalend with a hub mounted thereon and having a conical recess therein, saidintroducer cartridge comprising a flexible elongate tubular memberformed of a clear plastic and having a flow passage extendingtherethrough and having proximal and distal extremities, said flowpassage having a diameter, said distal extremity being tapered, and ahub formed of clear plastic secured to the proximal extremity of theflexible elongate tubular member, said hub of the introducer cartridgehaving a conical recess therein with a proximal extremity and with adistal extremity, the distal extremity of the conical recess having adiameter which is slightly less than the diameter of the flow passage inthe flexible elongate tubular member, said embolization device beingdisposed within the flow passage in the flexible elongate tubular memberof the introducer cartridge and being frictionally retained therein. 10.An apparatus for delivery of all embolization device into a vessel in ahuman body, said apparatus comprising an introducer catheter havingproximal and distal extremities and said distal extremity for beingdisposed in the vessel of the patient in a desired location, a deliverycatheter disposed within the introducer catheter and having proximal anddistal extremities, the distal extremity of the delivery catheter beingdisposed beyond the distal extremity of the introducer catheter andbeing located in the desired location in the vessel of the patient atwhich it is desired to place at least one embolization device, saiddelivery catheter having a hub with a conical recess therein, anintroducer cartridge comprising a flexible elongate tubular memberformed of a transparent material and having proximal and distalextremities and having a flow passage of predetermined diameterextending therethrough, said distal extremity of the flexible elongatetubular member of the introducer cartridge being tapered andfrictionally engaging the conical recess in the hub of the deliverycatheter to retain the introducer cartridge ill the hub of the delivercatheter, an embolization device disposed within the low passage of theflexible elongate tubular member of the introducer cartridge and beingfrictionally retained therein and a hub on the proximal extremity of theflexible elongate tubular member of the introducer cartridge, and havinga conical recess therein, said conical recess in the hub of theintroducer cartridge having proximal and distal extremities, the distalextremity of the conical recess of the introducer cartridge hub having adiameter slightly less than the predetermined diameter of the flowpassage in the flexible elongate tubular member of the introducercartridge.
 11. An apparatus as in claim 10, together with a stylet, saidstylet extending through the hub of the introducer cartridge hub andextending into the flow passage of the elongate tubular member forengaging and pushing the embolization device out of the introducercartridge, said introducer cartridge hub being formed of a clear plasticmaterial.
 12. An introducer cartridge together with a delivery catheter,said introducer cartridge comprising a flexible elongate tubular memberformed of a clear plastic and having a flow passage extendingtherethrough and having proximal and distal extremities, said flowpassage having a diameter, said distal extremity being tapered and anintroducer cartridge hub formed of clear plastic secured to the proximalextremity of the flexible elongate tubular member, said introducercartridge hub having a conical recess therein with a proximal extremityand with a distal extremity, the distal extremity of the conical recesshaving a diameter which is slightly less than the diameter of the flowpassage in the flexible elongate tubular member, said delivery catheterhaving a proximal end and having a delivery catheter hub mounted on theproximal end, said delivery catheter hub having a conical recesstherein, said conical recess in the delivery catheter hub being sized sothat the tapered distal extremity of the introducer cartridge engagesand seats within the conical recess of the delivery catheter hub and isfrictionally retained therein.